DRAFT: Add setKeyboardVisibility API.

chrome/common/extensions/api/experimental_input_virtual_keyboard.json

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 [
   {
     "namespace": "experimental.input.virtualKeyboard",
     "nodoc": true,
     "types": [],
     "functions": [
@@ skipping 36 matching lines @@
             },
             "description": "The keyboard event to be sent."
           },
           { "type": "function",
             "name": "callback",
             "optional": true,
             "description": "This function is called when the event processing is completed.",
             "parameters": []
           }
         ]
+      },
+      {
+        "name": "setKeyboardVisibility",
+        "type": "function",
+        "description": "Force the visibility of the keyboard.",
+        "parameters" : [
+          { "type": "boolean",
+            "name": "visible",
+            "description": "True to make the virtual keyboard visible, false to make it hidden."
+          }
+        ]
       }
     ]
   }
 ]